21 unprofessional email habits that make everyone hate you

With the onslaught of emails we receive every day, it's hard to imagine how anyone could keep up professional email habits at all times.

To make this task a little less daunting, we asked experts to highlight some of the least professional behaviours you could demonstrate when sending an email.

While mastering the art of good email etiquette doesn't mean sending out beautifully crafted prose each time -- that would take forever -- if you can avoid these bad habits, you'll be off to a great start. (Click on the arrows above or below to see the rest of the article)

Sending 'urgent' emails that aren't urgent

'Like the boy who cried wolf, if you abuse the urgent marker, it won't be long until no one will pay any attention to it,' Rosemary Haefner, chief human-resources officer for CareerBuilder, tells Business Insider.

And when you finally do send a truly urgent email, no one will pay attention to that one, either, she says.

Putting words in ALL CAPS

Unless you want to give your email recipient a heart attack, turn your CAPS LOCK off. And while you're at it, ease off on all the exclamation points.

Being too casual

While the tone of your message should reflect your relationship with the recipient, Haefner says, too much informality will make you come across as unprofessional.

She advises being judicious in your use of exclamation points, emoticons, coloured text, fancy fonts, and SMS shorthand.

What's more, not everyone can quickly decode acronyms, Rosalinda Oropeza Randall, an etiquette and civility expert and the author of 'Don't Burp in the Boardroom,' tells Business Insider.

'Be especially mindful if you work with people from different generations, have language barriers, or prefer a more traditional tone,' she says.

Being too stiff

At the same time, you don't want to come off as a robot.

'It's OK to add a bit of enthusiasm or personality to your emails,' Vicky Oliver, author of '301 Smart Answers to Tough Business Etiquette Questions' and '301 Smart Answers to Tough Interview Questions,' tells Business Insider.

She laments that sometimes she receives 'one-line emails that are so transactional they sound like an automaton is responding.'

Replying all

'Email is not a party in the break room -- it's a communication tool,' Haefner says. 'If you're responding to an email sent out to a group, be sure you are only hitting 'reply all' if your reply is truly necessary for everyone to receive.'

Cc'ing without approval

At the very least, sharing information that's not yours to share is annoying. It could also be a liability.

Whether you're cc'ing a client on an email where your boss said something about them or including a coworker on an email chain where another coworker shares personal information, 'No one likes to have someone else decide to cc someone without being asked first,' Randall says.

The best rule of thumb is to never assume it's OK to share an email with someone new to the conversation.

Bcc'ing

'I am not a big believer in blind copying people on emails,' Oliver says. 'When I have been bcc'd, the first thing I think is, 'If she is bcc'ing me on this, who else has she bcc'd on other emails?''

Bcc'ing conveys distrust and secrecy, she says.

'If you need to forward an email to someone who technically should not be on the chain, cut and paste the email into a separate email for that person,' Oliver suggests.

Sending emails at 3 a.m.

Oliver says that she's done it occasionally herself 'because sometimes you wake up very early and you're feeling productive.'

But she cautions that even in this 24/7 world, 'most people look at the time stamp and hold it against you if it shows some crazy hour in the morning. At best, they think you're a workaholic who doesn't have a life. At worst, they think you're obsessive.'

If inspiration strikes you at odd hours of the night, Oliver suggests writing the email, saving it in your drafts folder, and sending it during working hours.

Using a vague subject line

'It's me,' 'Hey,' or 'FYI' give the email recipient no indication of what you're emailing them about, and they're less likely to open your email as a result.

'None of these prompt immediate attention,' Randall says. 'A workplace email is best when it's clear and concise. Giving the recipient a clue can encourage them to read and reply quicker.'

Not including a subject line at all

As Amanda Augustine, a career expert for TopResume, previously told Business Insider, this can be irritating to the recipient, who is forced to open the email to figure out what it's about.

Starting a sentence in the subject line that you finish in the email's body

If you begin a thought or question that ends in the email, then the reader is once again forced to open the email, which is annoying, Augustine previously told Business Insider. The goal is to be clear and respectful of the recipient's time.

A ridiculous email address

If you're sending out an email in a professional capacity, whether it's to a client, colleague, or potential employer, avoid sending it from an unprofessional email account, Randall says.

Anything cutesy, sexy, vulgar, or nonsensical will set a negative tone from the get-go. If you insist on keeping 'S3xyCan1@netscape.net,' at the very least create a separate email account strictly for professional emails, Randall suggests.

Including cutesy or interminable quotes

'While having a tagline beneath your signature is acceptable, lengthy messages will probably go unread, take away from the professional tone, or just become burdensome,' Randall says. 'Keep your quotes and messages pertinent to your business or image.'

Sending too many personal emails

Jokes, touching stories, and motivational quotes sent on occasion could cheer up someone's day, Randall says, but they can quickly become tiresome.

'No matter how well-meaning you are, bombarding your coworkers' email on a daily basis can prompt them to auto-delete,' she says.

Including a confidentiality notice at the end of every email

'When sending content or photos via email, it is always up to the recipient's discretion whether it remains confidential,' Randall says. Instead, she suggests requesting confidentially before sending anything sensitive. This gives the recipient the ability to consent, and you'll have proof of that consent if anything gets out.

Being snippy

It can be tempting to show a little ire in your follow-up email, especially when you've been waiting on something that hasn't been delivered. Don't, advises Oliver.

'People always remember the mean email,' Oliver says, 'which is why you must not send one.'

Instead, she advises writing the email you want to send, saving it in your drafts folder for 48 hours, and then revising it to take out the snippiness.

'It will help you accomplish your goal faster because you will come off as patient and professional as opposed to snarky,' she says.

Being curt

If you know the person really well, you can sometimes dispense with the niceties, Oliver says.

'But if the person to whom you're writing is a business colleague or a client, err on the side of politeness. Use words like 'please,' 'thank you,' and sign off with a word like, 'Best,'' she says.

Numerous typos

'Sent from my iPhone,' is no excuse for sloppy emails.

While Oliver says one typo here and there is becoming more acceptable because everyone is sending emails from their phones, more than one per email is unprofessional.

If the email is important enough to send out while you're on the run, it's important enough to look over before you send it out.

Annoying punctuation

If you choose to use an exclamation point, use only one to convey excitement, says Barbara Pachter, author of 'The Essentials of Business Etiquette.'

'People sometimes get carried away and put a number of exclamation points at the end of their sentences. The result can appear too emotional or immature,' she writes in her book. 'Exclamation points should be used sparingly in writing.'

Unprofessional fonts

Purple Comic Sans has a time and a place -- maybe? -- but for business correspondence keep your fonts, colours, and sizes classic.

The cardinal rule: Your emails should be easy for other people to read.

'Generally, it is best to use 10- or 12-point type and an easy-to-read font such as Arial, Calibri, or Times New Roman,' Pachter advises.

As for colour, black is the safest choice.

Going too long

Most people spend seconds -- not minutes or hours -- reading an email, and a lot of people only skim them, so write your email accordingly.

Large blocks of text are hard to read, so it's better to break emails into short paragraphs, Haefner says. Bullet points or numbered lists are even easier to digest.

You can also use bold or italics to highlight important parts of your message, but you should do so sparingly.